SUBSCRIBER SERVICES ARRANGEMENT FOR MOBILE TELECOMMUNICATIONS SYSTEM PROVIDING PABX ACCESS

Abstract: The invention relates to a subscriber services arrangement (100) in a telecommunications system (MTN, PTN, PSTN) which is utilized by a plurality of mobile telephone stations (MS1, MS2), wherein at least one private automatic branch exchange (PABX1) is intended to provide PABX services to a predetermined group of subscribers of the plurality of mobile telephone stations mentioned.

Description: Subscriber services arrangement for mobile telec-XOTπunications system providing PABX access. TECHNICAL FIELD The invention relates to a method and to an arrangement which relate to a mobile telephone network which is utilized by a plurality of mobile telephone stations. More particularly, the invention relates to a telephone system subscriber service arrangement and to a method of directing calls in a telephone system. BACKGROUND OF THE INVENTION Historically, business telephone subscribers, i.e. employees using a telephone at their office, have been using a statio¬ nary private automated branch exchange (PABX) telephone. As soon as such a subscriber leaves his office, any incoming call has to be diverted to a secretary, a colleague etc. With newer technology, a business telephone subscriber may have a cordless telephone that makes him at least partially reachable when he is away from his office. The european patent application EP 462727 A2 describes how a limited number of mobile telephone stations in a mobile telephone network are given access to business services that normally only are available to the business telephone sub¬ scribers using the private exchange (PABX) . According to the european application, only mobile stations located in a limited area in the mobile network close to the private exchange are given access to the services. The application does not explain how services can be accessed by mobile stations located in a wide area. Employees who need to make and receive telephone calls wherever they are, have to use mobile telephone stations that have no direct connection to a PABX. Thus, the alternatives available today are to use either a stationary PABX telephone or a cordless telephone with limited range of use, using a private numbering plan, or a mobile telephone station with full mobility but with no PABX connec¬ tion, using a public numbering plan. In other words, with full mobility you lose business services and communicationpossibilities that you normally have within a PABX or within a private telecom network (PTN) comprising a number of PABXs. DISCLOSURE OF THE INVENTION The aforesaid problem to use business services of a private telecom network and still maintain movability is solved in accordance with the invention. One object of the present invention is thus to enable a user of a mobile telephone in a mobile telephone network to use subscriber services which are normally only available to subscribers located in a private telephone network. The intention of the invention is to enable the user to avail himself/herself of the subscriber services irrespective of where the mobile telephone is located in the mobile network. This object is achieved with an inventive arrangement which is connected to both the mobile telephone network and to the private network, and by an inventive method by means of which any call from the mobile telephone can be directed to the inventive arrangement irrespective of where the mobile telephone is located in the mobile telephone network. Another additional object of the invention is to enable use of services even if the user is located in a mobile telephone network other than the one connected to the arran- gement. This object is achieved by another inventive methodby means of which any call can be directed to the inventive arrangement. The advantage with the invention is that the subscriber can act as if he/she belongs to the private network even if he/she is located in any of the mobile telephone networks connected to the private network. DESCRIPTION OF THE DRAWINGS So that the invention will be more readily understood and other features thereof made apparent, the invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 shows schematically a telephone system according to the present invention and illustrates an inventive method of directing a call from a mobile telephone to the inventive arrangement; and Figure 2 shows schematically a telephone system according to the present invention and illustrates an inventive method of directing a call from a mobile telephone in a first mobile telephone network to the inventive arrangement in another mobile telephone network. DESCRIPTION OF PREFERRED EMBODIMENTS Figure 1 illustrates a telephone system MTN, PTN, PSTN, which includes a mobile telephone network PTN, a public telephone network PSTN and a private telephone network PTN. The figure schematically shows the mobile telephone networkMTN with its connections, on the one hand, to the public switched telephone network PSTN and, on the other hand, to the private telecom network PTN in accordance with the invention. The mobile telephone network MTN is utilized by a plurality of mobile telephone stations which in the figure are represen¬ ted by mobile telephone stations MSI and MS2. The mobile telephone station MSI is supposed to be used by a normal mobile telephone subscriber using the mobile telephone network MTN, while the mobile telephone station MS2 is used by a subscriber belonging to the private telecom network PTN. In the mobile telephone network MTN, the mobile telephone station MSI, in a conventional manner, communicates by radio with e.g. a base station BS which by e.g. a pulse code modulation (PCM) link, is connected to a mobile services switching center MSC1 which in its turn is connected to the public switched telephone network PSTN via another mobile services switching center MSC2. It is to be understood that there can be a plurality of base stations and mobile services switching centers in the mobile telephone network MTN. Subscriber information about a subscriber using the mobile telephone station MSI is stored, in a manner known per se, in a home location register HLR connected to the mobile services switching centers MSC1 and MSC2. Subscriber information about any subscriber belonging to the private telecom network PTN, using the mobile telephone station MS2, is also stored in the home location register HLR or in another data storage device (not shown) separated from the home location register. The private telecom network PTN is shown as comprising a single private automatic branch exchange PABX2 to which a plurality of stationary telephones (not shown) may be con¬ nected. It is, however, to be understood that the private telecom network PTN may comprise a number of PABXs and a number of mobile telephone stations MS2. It is also to be understood that the private telecom network PTN not neces¬ sarily must comprise the private automatic branch exchange PABX2, but may comprise just a number of mobile telephone stations corresponding to MS2, served by the mobile telephone network MTN. In accordance with the invention, to provide PABX services to the subscriber of the mobile telephone station MS2 of the same nature as provided to the subscribers of the stationary telephones connected to the private automated branch exchange PABX2 in the private telecom network PTN, the mobile telephone network MTN comprises a subscriber services arrangement 100 which includes a private automatic branch exchange PABX1. Instead ofusing a physical private automaticbranch exchange, the functionality of a private automatic branch exchange may be emulated, in software, in the mobile telephone networkMTN, e.g. in a mobile services switching center such as MSC2. The emulated private automatic branch exchange may, as an alter¬ native, be located closer to the mobile telephone station MS2 in the mobile telephone network, e.g. in a base station controller (not shown) controlling the base station BS. By means of the private automatic branch exchange PABX1, it will be possible to provide any reguested PABX service to the subscriber of the mobile telephone station MS2. To enable communication between the mobile telephone station MS2 and subscribers in the private telecom network PTN, the private automatic branch exchange PABX1 in the mobile tele¬ phone network MTN, will use an available connection, wired or wireless trunks, to the private automatic branch exchange PABX2 in the private telecom network PTN. The communication between the private automatic branch exchanges PABX1 and PABX2 may take place according to a protocol DPNSS 1, Q-SIG or any other protocol in a manner known per se from interconnections between PABXs in private telecom networks. DPNSS 1 and Q-SIG are the two standards today to interconnect PABXs. DPNSS 1 stands for Digital Private Network Signalling System No. 1 and Q-SIG refers to the Q reference point in a digital access as specified by CCITT. In the embodiment shown in the figure, in connection with a set-up of a call from the mobile telephone station MS2, any number dialled from that mobile telephone station MS2 by a subscriber who is a subscriber of the private telecom network PTN shall be routed to the private automatic branch exchange PABX1. This is accomplished in that the network address of the private automatic branch exchange PABX1 is added as a prefix to the dialled number by the mobile services switching center MSC1, as controlled by the home location register HLR, before the call set-up is sent on into the network. In the private automatic branch exchange PABX1, the calling subscriber's mobile station integrated services digital number (MSISDN) or directory number is translated into a pointer to his service profile. Figure 1 illustrates with the aid of arrows the signalling required by an inventive method to direct a call from a mobile telephone MS2 in the mobile telephone network MTN to the subscriber service arrangement 100. According to the inven¬ tive method, the call is directed first to the subscriber services arrangement 100, irrespective of the telephone unit in the telephone system MTN, PSTN, PTN for which the call is intended. The method comprises the steps of: - Transmitting an activating message from the mobile unit (MS2) to the mobile services switching centre 1. The mobile services switching centre MSC1 is referred to here as the first mobile services switching centre 1. The activating message 1 is sent, for instance, in conjunction with the mobile telephone MS2 first entering the cell area managed by the first mobile services switching centre MSC1. Transmitting a subscriber data query 2 from the first mobile services switching centre MSC1 to the home location register HLR. The subscriber data query 2 includes a request for subscriber data for the mobile telephone MS2. Transmitting a subscriber data response 3 from the home location register HLR to the mobile services switching centre MSC1. The subscriber data response 3 includes an address to the subscriber services arrangement 100. Storing the subscriber response 3 in a register in the mobile services switching centre MSC1. - Sending a first call signal 4 from the mobile unit MS2 to the mobile services switching centre MSC1. The call is intended for a unit in the telephone system MTN, PTN, PSTN, for example a unit A3. The unit for which the call is intended is unimportant to the inventive method. - Processing the first call signal 4 in the switching centre MSC1 to form a second call signal 5. This second call signal includes the address of the subscriber services arrangement 100 after having been processed. - Directing the second call signal 5 to the arrangement 100 with the aid of the address, via a second mobile services switching centre MSC2. A call placed towards a subscriber of the private telecom network PTN, using the mobile telephone station MS2, will be passed on as already have been described above by the private automatic branch exchange PABX1 by using the subscriber's MSISDN. A predetermined security analysis, e.g. in the home location register HLR, will verify that only calls from the private automatic branch exchange PABX1 using the sub¬ scriber'sMSISDN, will be accepted. The home location register HLR will verify that the call comes from the private automatic branch exchange PABX1 by a predetermined analysis. If the result is positive, the call will proceed as a normal call to an ordinary mobile telephone subscriber. In principle, the below three alternatives can be identified that will enable a subscriber to use his services in the private automatic branch exchange PABXl: 1. The private automatic branch exchange PABXl will monitor all calls to and from the mobile telephone station MS2 for any Dual Tone Multiple Frequency (DTMF) signalling from the mobile telephone station MS2. Valid service codes signalled by using DTMF, will be acted upon in PABXl as specified according to a predetermined specification. If no call is established and the subscriberwants to manipulatehis serviceprofile in theprivate automaticbranch exchange PABXl, he can call a predetermined number and then dial the service code that will be carried by in-band DTMF signals. 2. Instead of using DTMF, it will be possible to use any available mechanism in the mobile telephone network in order to communicate between the mobile telephone station MS2 and the private automatic branch ex¬ change PABXl. An example of such a mechanism is the Mobile Application Part (MAP) operation "Unstruc¬ tured Supplementary Service Data" that is specified in the Global System for Mobile communication (GSM) . An advantage of the above mechanism is that it enables the private automatic branch exchange PABXl to communicate e.g. alerting messages to the mobile telephone station MS2 by sending text strings to the text window of the mobile telephone station. This is not possible when alternative 1 above is used. 3. Another alternative to allow the subscriber to use his services with no call active, is to dial a service control sequence, and then push the send key as for a normal GSM subscriber service. The private automatic branch exchange PABXl will receive the service code in a call set-up messaged from the mobile services switching center. It will be obvious to one of normal skill in this art that the method described with reference to Figure 1 can also be applied when the mobile telephone MS2 is located in another mobile telephone network MTNX, a so-called first mobile telephone networkMTNX different to the aforedescribed mobile telephone network MTN, which in the exemplifying embodiment is referred to as a second mobile telephone network MTN. This embodiment is illustrated in Figure 2. The two networks MTNX and MTN are handled by different operators. The first mobile telephone network MTNX comprises a first mobile services switching centre MSCX in whose cell area the mobile telephone MS2 is located. An inventive method for directing a call, any call, from the mobile telephone MS2 to the subscriber services arrangement 100 is illustrated in Figure 2 and comprises the steps of: - Transmitting an activating message 11 from the mobile unit MS2 to the first mobile services switching centre MSCX. - Sending a subscriber data query 12 from the mobile services switching centre MSCX in the first network MTNX to the home location register HLR in the second network MTN. - Sending a subscriber data reply 13 from the home location register HLR in the second network MTN to the first mobile services switching centre MSCX in the first network MTNX. The subscriber data reply 13 includes an address to the earlier mentioned data storage device. The data storage device includes an address to the subscriber services arrangement 100. - Sending a second subsciber data query from the mobile services switching centre MSCX to the data storage device. - Sending a second subscriber data reply from the data storage device to the mobile services switching centre MSCX. The second reply includes the address to the subscriber services arrangement 100. Storing the second reply in the first mobile services switching centre MSCX. - Sending a first call signal 14 from the mobile unit MS2 to the mobile services switching centre MSCX. The call is intended for any unit in the telephone system, for example the unit A3. - Processing the first call signal 14 to obtain a second call signal 15 which includes the address to the subscriber services arrangement 100. - Directing the second call signal 15 to the arrangement 100 in the second network MTN. It is to be understood that the invention can be used for data transmission. Another possibility is that the mobile tele- phone contains an arrangement for switching off the automatic connection to the subscriber service arrangement 100. The fact that PABX oriented services will be available to subscribers of mobile telephone stations, will give mobile telephony the following important merits: It will be possible to use services which are not normally available to a normal subscriber of a mobile telephone station. These services include i.a. Intrusion (to allow intrusion into an ongoing call, e.g. to ask an important question or give important information) and Select Call Acceptance (to allow certain numbers to complete calls so that when the subscriber is at a meeting, a few important col¬ leagues will be able to get through without letting all other incoming calls be completed) .

Claims: CLAIMS 1. A subscriber services arrangement (100) in a telecom¬ munications system (MTN, PTN, PSTN) , which includes a mobile network (MTN) and a private telecommunications network (PTN) , wherein the subscriber services arrangement (100) includes a first private automatic branch exchange (PABXl) which is connected to the mobile network (MTN) , wherein the subscriber services arrangement (100) is also connected to a second private automatic branch exchange (PABX2) in the private network (PTN) , wherein the second private automatic branch exchange (PABX2) handles subscriber services for subscribers (A3, MS3) in the private network (PTN), wherein a predeter¬ mined group of mobile units (MSI, MS2) have arrangements for connenction to the subscribers services arrangement (100) irrespective of where these mobile subscribers are located in the mobile network (MTN) , so that said predetermined group of mobile units (MSI, MS2) in the mobile telephone network (MTN) are therewith included in the private network (PTN) . 2. A subscriber services arrangement (100) in a telecom¬ munications system (MTN, PTN, PSTN) , which includes a private telecommunications network (PTN) and a first mobile network (MTNX) and a second mobile network (MTN) , which mobile networks comprises arrangement for connection with each other, wherein the subscriber services arrangement (100) includes a first private automatic branch exchange (PABXl) which is connected to the secondmobile network (MTN) , wherein the subscriber services arrangement (100) is also connected to a second private automatic branch exchange (PABX2) in the private network (PTN) , wherein the second private automatic branch exchange (PABX2) handles subscriber services for subscribers (A3, MS3) in the private network (PTN) , wherein a predetermined group of mobile units (MS2) in the first mobile network (MTNX) have arrangements for connenction to the subscribers services arrangement (100) irrespective of where these mobile subscribers are located in the mobile network (MTNX) , so that said predetermined group of mobile units (MS2) in the first mobile telephone network (MTNX) are therewith included in the private network (PTN) . 3. An arrangement (100) according to Claim 1 or 2, which comprises means for including the predetermined group of mobile units in the number plan of the private network. 4. An arrangement (100) according to Claim 1, 2 or 3, which comprises means for including the predetermined group of mobile units to use the subscriber services of the private network. 5. An arrangement (100) according to Claim 1, 2, 3 or 4, wherein the arrangement comprises means for monitoring all calls including a mobile telephone (MS2) with regard to certain predetermined keyword set signals in the calls. 6. An arrangement (100) in a telecommunications system (MTN, PTN, PSTN) according to Claim 1, 2, 3 or 4, wherein the telecommunications system includes signal processing means which enables transparent communication between the arran¬ gement (100) and the mobile telephone (MS2) . 7. An arrangement (100) in a telecommunications system (MTN, PTN, PSTN) according to Claim 6, wherein the signal processing means are arranged to use a standardized protocol formobility 8. An arrangement in a telecommunications system (MTN, PTN, PSTN) according to Claim 1, 2, 3, 4, 5, 6 or 7, which system comprises an emulation device, so that the the function of the first private automate exchange (PABXl) can be emulated in the system. 9. An arrangement according to Claim 8, wherein at least one private automatic branch exchange is emulated in a mobile services switching center (MSC1, MSC2) in themobile telephone network (MTN) . 10. A method for handling a mobile unit (MS2) in a mobile network (MTN) included in a telecommunication system (MTN, PTN, PSTN) , which mobile unit (MS2) is a subscriber in a private telecommunications network (PTN) included in the telecommunication system (MTN, PTN, PSTN) , which system comprises a subscriber services arrangement (100) connected to the private telephone network (PTN) , wherein the mobile telephone network (MTN) includes a home location register (HLR) in which the mobile unit is permanently registered as belonging to the mobile telephone network (MTN) , wherein the mobile telephone network (MTN) includes a mobile services switching centre (MSC1) which handles calls from the mobile unit (MS2) ; and wherein the mobile services switching centre (MSC1) is able to establish a connection with both the home location register (HLR) and with said arrangement (100) , said method comprising the steps of: sending an activating message (1) from the mobile unit (MS2) to the mobile services switching centre (MSC1) ; sending a subscriber data query (2) from the mobile services switching centre (MSC1) to the home location register (HLR) ; - sending a subscriber data reply (3) from the home location register (HLR) to themobile services switching centre (MSC1) , said reply (3) pointing out the subscriber services arran¬ gement (100) ; - storing an arrangement address to the subscriber services arrangement (100) in the mobile services switching centre (MSC1) . 11. A method according to claim 10, wherein the method comprises the following additional steps: - sending a first call signal (4) from the mobile unit (MS2) to the mobile services switching centre (MSC1) , said call being intended for a unit, any unit, in the telecommunications system (MTN, PTN, PSTN) ; - restructuring the first call signal (4) to obtain a second call signal (5) which includes the address of the subscriber services arrangement (100) ; and - directing, with the aid of said arrangement address, the second call signal (5) to the subscriber services arrangement (100) . 12. A method for handling a mobile unit (MS2) in a first mobile network (MTNX) included in a telecommunication system (MTN, MTNX, PTN) , which mobile unit (MS2) is a subscriber in a private telecommunication network (PTN) included in the telecommunication system, which system (MTN, MTNX, PTN) comprises a subscriber services arrangement (100) in a second mobile telephone network (MTN) , wherein the subscriber services arrangement (100) is connected to the private telephone network (PTN) and the second mobile telephone network (MTN) includes a home location register (HLR) in which the mobile unit is permanently registered as belonging to the said second mobile telephone network (MTN) , wherein the first mobile telephone network (MTNX) includes a mobile services switching centre (MSCX) which handles calls from the mobile unit (MS2) , wherein the mobile services switching centre (MSCX) is able to set-up a connection with both the home location register (HLR) and with the subscriber services arrangement (100) in the second mobile telephone network (MTN) , the method comprising the steps of: sending an activating message (11) from the mobile unit (MS2) to the mobile services switching centre (MSCX) ; sending a subscriber data query (12) from the mobile services switching center (MSCX) in the firstmobile telephone network (MTNX) to the home location register (HLR) in the second mobile telephone network (MTN) ; - sending a subscriber data reply (13) from the home location register (HLR) in the second mobile telephone network (MTN) to the mobile services switching centre (MSCX) in the first mobile telephone network (MTNX) , said reply (13) pointing out the subscriber services arrangement (100) ; - storing an arrangement address to the subscriber services arrangement (100) in the mobile services switching centre (MSCX) . 13. A method according to claim 12, wherein the method comprises the following additional steps: - sending a first call signal (14) from the mobile unit (MS2) to the mobile services switching centre (MSCX) in the first mobile telephone network, this call being intended for any unit in the telecommunications system (MTN, PTN, PSTN) ; - restructuring the first call signal (14) to obtain a second call signal (15) which includes the address of the subscriber services arrangement (100) ; and - directing, with the aid of said arrangement address, the second call signal (15) to the subscriber services arrangement (100) in the second network (MTN). 14. A method in a telecommunication system (MTN, PTN, PSTN) according to claim 10 or 12, which system (MTN, PTN, PSTN) comprises a data storage device the data storage device includes an address to the subscriber services arrangement (100) , said method comprising the additional steps of: - sending a second subsciber data query from the mobile services switching centre (MSC1, MSCX) to the data storage device; - sending a second subscriber data reply from the data storage device to the mobile services switching centre (MSC1, MSCX) , which reply includes the address to the subscriber services arrangement (100) ;

Inventors: BERGGREN KARL VIKTOR, ROBERT GUY MIKAEL, BERGGREN, KARL, VIKTOR, ROBERT, GUY, MIKAEL
Applicants: ERICSSON TELEFON AB L M, TELEFONAKTIEBOLAGET LM ERICSSON
Application year: 1994
Main classification: H04Q7
IPC codes: H04M3, H04Q3, H04W84, H04W88